3 Answers
3

eCryptfs would be a good choice (Ubuntu encrypted home directory uses ecryptfs) if you want to encrypt /dev/sda4 which is mounted as /home/igor/Personale type ext4

You don't have to re-install anyway. ecryptfs is flexible (you can encrypt folders or partitions) and easy to use, it is layered on top of the current file system - ext4 in your case. Basically you have a partition/block device, create file system and mount it, then use ecryptfs to encrypt it.

In your case, it's /dev/sda4, to encrypt it
NOTE: although this process retains existing data I strongly recommend backing up to a different partition or external HDD. Because later on we need to copy it back to get data encrypted (existing data won't get encrypted).

Done. Existing data won't be encrypted anyway, you can delete existing data and copy if from backup (that's why I recommended backing up, a data swap is needed to activate encryption on existing files). Use rsync for backup/restore:

rsync -axHAX /backup /home/igor/Personale

BTW: you can see the encrypted partition use findmnt or mount, e.g
/home/terry/topsecret on /home/terry/topsecret type ecryptfs (rw,ecryptfs_sig=633937dbcf1fef34,ecryptfs_cipher=aes,ecryptfs_key_bytes=16,ecryptfs_unlink_sigs)

When run on a given encrypted directory for the first time, encfs will take you through setting the password and encryption options.

To unmount the encrypted folder, type

fusermount -u /path/to/decrypted

To mount the encrypted directory again, type the same command you used to encrypt it:

encfs /path/to/encrypted /path/to/decrypted

Note that encryption is quite different from Unix permissions ("only my user can access..."). In short, any person and only a person with the credentials (password to the encrypted directory) can decrypt it. That is rather the point of it, because anyone with physical access to your machine can become root, and consequently -- also any user, including you. It is as simple as booting the computer with a live cd or taking out the drive and connecting it to another system.